<html>
    <head>
        <style>
            body {
                padding: 100px;
                margin: 0;
            }

            #box {
                width: 100px;
                height: 100px;
                background-color: #0077ff;
            }

            [data-layout-correct="false"] {
                background: #dd1144 !important;
                opacity: 1 !important;
            }
        </style>
    </head>
    <body>
        <div id="root"></div>
        <script type="module" src="/src/imports/optimized-appear.js"></script>
        <script type="module" src="/src/imports/script-assert.js"></script>

        <script type="module">
            const {
                motion,
                startOptimizedAppearAnimation,
                optimizedAppearDataAttribute,
                motionValue,
            } = window.Motion
            const { matchOpacity } = window.Assert
            const root = document.getElementById("root")

            const duration = 0.5

            // This is the tree to be rendered "server" and client-side.
            const Component = React.createElement(() => {
                React.useLayoutEffect(() => {
                    const startTime = performance.now()
                    while (performance.now() - startTime < 100) {}
                })

                return React.createElement(motion.div, {
                    id: "box",
                    initial: { opacity: 0 },
                    animate: { opacity: 1 },
                    transition: { duration, ease: "linear" },
                    /**
                     * On animation start, check the values we expect to see here
                     */
                    onAnimationStart: () => {
                        const { opacity: initialOpacity } =
                            window.getComputedStyle(box)
                        const opacityAsNumber = parseFloat(initialOpacity)
                        if (opacityAsNumber < 0.4 || opacityAsNumber > 0.6) {
                            showError(
                                box,
                                `opacity should be roughly less than 0.5 at animation start`
                            )
                        }
                    },
                    [optimizedAppearDataAttribute]: "a",
                })
            })

            // Emulate server rendering of element
            root.innerHTML = ReactDOMServer.renderToString(Component)

            startOptimizedAppearAnimation(
                document.getElementById("box"),
                "opacity",
                [0, 1],
                {
                    duration: duration * 1000,
                    ease: "linear",
                },
                (animation) => {
                    // Hydrate root mid-way through animation
                    setTimeout(() => {
                        ReactDOMClient.hydrateRoot(root, Component)
                    }, (duration * 1000) / 2)
                }
            )
        </script>
    </body>
</html>
